aspartic acid and α-amino-n-butyric acid. The identification of the last two
acids was not very certain according to the author’s opinion since the
spotes were quite weak. According to him the obtained amino acids cannot
originate from living organisms since their growth would have been stopped
by the high temperature and the added at the end of the experiment
mercury dichloride (HgCl₂), as well as by the addition of barium base
[Ba(OH)₂] and sulphuric acid (H₂SO₄) at the time of analysis.
The results from Miller’s experiment were confirmed and
supplemented by new syntheses of other scientists. Various amino acids,
aldehydes, amines, amides, carbohydrates, purine and pyrimidine
bases, polypeptides, polynucleotides and other important biological
compounds have been obtained. Except the basic components of the
gas mixture of methane, ammonia and hydrogen, carbon oxide, carbon
dioxide, hydrogen cyanide, nitrogen, phosphoric compounds, and other
compounds have also been used. As energy sources along with the spark
and silent electric discharges, UVlight, radioactive irradiations, γ- and βrays,
rapid neutrones and X-rays have been reported in the Proceedings of several
International conferences: the first one — on the origin of life on Earth held in
Moscow in 1957 (Proceedings……, 1959); the second — on the origin of prebiological
systems and their molecular mechanisms, held in Wakulla Springs, Florida in 1963
(Proceedings…., 1965); the Congress in Espoo, Finland in 1988 (TwentySeventh…., 1989), etc.
A detailed review on this problem is made by Oró at al. (1990).
A serious tribute in that trend represent the studies of Fox and Harada
(Fox, 1960; Fox, Harada, 1960,1961; Harada, Fox, 1964) related to the
thermal polycondensation of amino acids and the obtaining of polypeptides
in the absence of nucleotide code. According to these authors a synthesis
of amino acids as well as of more complex proteinoids can be achieved by
simple methods in the conditions of normal atmospheric pressure and a
temperature of the order of 100—210°C. Under such conditions in the
presence of significant quantities of aspartic and glutamic acids, a
spontaneous polymerization of almost all amino acids takes place leading
to the formation of polypeptides of a molecular weight from 3000 to 9000
daltones. This process is enhanced by the addition of polyphosphoric acid
Figure 1–5. An apparatus for abiogenic synthesis under conditions resembling the supposed ones in the primeval earth atmosphere (Adapted after Miller, 1953).